Displays are widely applied due to numerous advantages such as thin bodies, energy saving, radiation-free, etc. Most displays available on the market are backlight-type displays, and such display includes a display panel and a backlight module. The working principle of the display panel is placing liquid crystal molecules between two parallel substrates, and applying a driving voltage on the two substrates to control rotation directions of the liquid crystal molecules, for refracting rays of the backlight module to generate images.
A thin film transistor-liquid crystal display (TFT-LCD) gradually occupies the dominant position in the display realm at present because of its properties such as low energy consumption, superior image quality and relatively high production yield, etc. Identically, the TFT-LCD includes a display panel and a backlight module. The liquid crystal panel includes a color filter (CF) substrate and a thin film transistor (TFT) substrate. The opposite internal sides of the substrates have transparent electrodes. A layer of liquid crystal (LC) molecules are interposed between the two substrates. The display panel alters the polarization state of light by control of the electric field on the orientation of liquid crystal molecules, and achieves the objective of display by blocking or unblocking the optical path by a polarizer.
The production of TFT devices with high performance is the basis of the quality LCD. The protective layer of the TFT commonly employs silicon nitride. The protective layer has a relatively small relative dielectric constant, but the relative dielectric constant of silicon nitride is relatively high, and the capacitance is large. Signals can be easily disturbed.